1. Technical Field.
The present application relates generally to a medical device, such as a catheter, for use in transporting fluids. More particularly, the application relates to a dual lumen catheter for transporting a bodily fluid for extracorporeal treatment, and returning the treated fluid to the body.
2. Background Information.
Dual lumen catheters are commonly used for transporting a bodily fluid for treatment external of the patient's body, a process generally referred to in the medical field as “extracorporeal” treatment, and thereafter returning the treated fluid to the body. A fluid is withdrawn from the body through one of the lumens of the catheter, generally referred to as the withdrawal lumen. The fluid is subjected to a treatment process, and thereafter returned (or “infused”) to the body through the other lumen, generally referred to as the infusion lumen.
In many cases, the extracorporeal treatment is carried out as part of a hemodialysis procedure. During hemodialysis, blood is withdrawn from a blood vessel through the withdrawal lumen and routed to a dialyzer for cleansing. The cleansed blood is then returned to the blood vessel through the infusion lumen. When such a catheter is used for hemodialysis, it is generally inserted into the body through the jugular vein, the subclavian vein or the femoral vein. In addition to hemodialysis, extracorporeal catheters can also be used for other procedures in which a fluid is removed from the body for treatment and later returned to the body.
A variety of hemodialysis catheters are available. Among the types of commercially available catheters are: 1) a dual lumen catheter having one lumen (e.g., the blood infusion lumen), that terminates distal to the other lumen (e.g., the blood withdrawal lumen). Some catheters of this type are provided with a midline split (e.g., the Uldall catheter), while others do not have such a split (e.g., the COOK® DDS catheter); 2) a catheter having a slitted valve in the distal tip that acts as a pressure valve opening. This valve opens inwardly for blood aspiration, outwardly for blood infusion, and remains closed when not in use (e.g., the Groshong catheter); 3) polyester-cuffed central venous silicone catheters that are tunneled underneath the skin to reduce infection (e.g., Broviac, Leonard and Hickman catheters); 4) a dual lumen catheter having a tapered tip and two adjacent holes communicating with one lumen just proximal to the tip to assist with outflow, and two adjacent holes communicating with the other lumen (180 degrees removed) just proximal to the first set of holes to assist with inflow (e.g., the Mahurkar catheter); 5) a dual lumen catheter having a diverting structure consisting of a shoulder that has a straight up distal face and a sloped proximal face to reduce access recirculation and raise pressure in the vicinity of the inlet aperture (U.S. Pat. No. 6,409,700); and 6) a catheter designed for femoral approach having two sets of staggered side ports, resulting in a total of four side ports.
Typically, dual lumen hemodialysis catheters have fixtures and related structure at the proximal end that are larger than the diameter of an introducer device through which the catheter is inserted into the vessel. As a result, splittable introducer sheaths, such as the PEEL-AWAY® introducers commercially available from Cook, Incorporated, of Bloomington, Ind., are often utilized for insertion of the catheter. Although such introducers are generally effective for such use, it would be desirable if the catheter insertion procedure could be simplified in a manner such that a separate introducer sheath would not be required. Eliminating the introducer device simplifies the procedure by omitting the sheath removal step that must otherwise be carried out by the physician, and also reduces the overall cost of the procedure. However, since many conventional hemodialysis catheters have stepped or otherwise non-tapered distal (e.g., entry) portions, these catheters are generally not amenable to non-traumatic insertion in the vessel without the use of a tapered introducer and/or dilator.
It would be desirable to provide a dual lumen catheter for use in the extracorporeal transport of bodily fluids that is capable of insertion into a vessel in substantially non-traumatic fashion, and without the necessity of utilizing an introducer apparatus.